Scientists find bigger than expected polar ice melt

26th February 2009, 0 comments

The frozen and often inaccessible polar regions have long been regarded as some of the most sensitive barometers of environmental change and global warming because of their influence on the world's oceans and atmosphere.

Geneva -- Icecaps around the North and South Poles are melting faster and in a more widespread manner than expected, raising sea levels and fuelling climate change, a major scientific survey showed Wednesday.

The International Polar Year survey found that warming in the Antarctic is "much more widespread than was thought," while Arctic sea ice is diminishing and the melting of Greenland's ice cover is accelerating.

The frozen and often inaccessible polar regions have long been regarded as some of the most sensitive barometers of environmental change and global warming because of their influence on the world's oceans and atmosphere.

Preliminary findings from the two-year survey by thousands of scientists revealed new evidence that the ocean around the Antarctic has warmed more rapidly than the global average, the World Meteorological Organisation and the International Council for Science said in a statement.

Meanwhile, shifts in temperature patterns deep underwater indicated that the continent's land ice sheet is melting faster than reckoned.

"These changes are signs that global warming is affecting the Antarctic in ways not previously suspected," the statement added. "These assessments continue to be refined, but it now appears that both the Greenland and the Antarctic ice sheets are losing mass and thus raising sea level, and that the rate of ice loss from Greenland is growing."

Shrinking sea ice was expected around Antarctica, while Arctic sea ice decreased to its lowest level since satellite records began.

During the survey in 2007 and 2008, special expeditions in the Arctic also found an "unprecedented rate" of floating drift ice, providing "compelling evidence of changes" in the region.

But the focus was on the erosion of land-based ice sheets of Greenland and the Antarctic, which hold the bulk of the world's freshwater reserves and can generate sea level changes of global scale as they melt.

"That was an urgent question three years ago and I think today it's now a more urgent question," IPY director David Carlson told journalists.

When the survey began two years ago, those areas were viewed as largely stable despite some worrying signs of fringe melting.

"The message of IPY is loud and clear: what happens in the polar regions affects the rest of the world and concerns us all,” the joint statement concluded.

The survey also revealed that the melting has the potential to feed more global warming as the permafrost melts faster.

Permafrost, the expanse of continuously frozen soil in polar land areas, was found to have larger pools of carbon than expected and the melting could unleash more greenhouse gases into the atmosphere.

The scientists also found that global warming caused substantial changes that were tantamount to a greening of the Arctic landscape.

Vegetation and soil were changing in the region, with shrubbery taking over grassland and tree growth shifting according to changing snowfall, while insect and fungi infestation increased and species move from lower latitudes into polar regions.

Those shifts also disrupted native animals, hunting and local livelihoods, the scientists found.

In some instances, reindeer raised by local herders lost grazing pasture while their migration routes became blocked by building in areas previously regarded as uninhabitable.

The survey around both poles was the first of its kind for half a century, revisiting areas that have not been seen since the 1950s and mobilising 10,000 scientists around the world.